Telephone-exchange system.



A. RAYNSFORD.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED SEPT-H, 19i6- Patented Apr. 10,1917.

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ARTHUR RAYNSFORD, OF NEW YORK, N.

Y., ASSIGNOR TO WESTERN ELECTRIC GOM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed September 11, 1916.

To all whom it may concern:

Be it known that I, ARTHUR RAYNSFORD, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone eX- change systems, its object being the production of improved signaling means for such systems.

In accordance with a feature of this invention, a link circuit is provided with two relays which cooperate with each other and with the supervisory relay, when the link circuit joins two telephone lines, to connect interrupter mechanism in circuit with a signaling device to cause the intermittent operation thereof.

This invention is illustrated in the accompanying drawing, in which all apparatus is shown in its normal and unactuated condition.

There is shown in the drawing a telephone exchange system containing one embodiment ofthis invention, and comprising subscribers lines A and B terminating at the central oflice, and a cord circuit C thereat for connecting the subscribers lines. It will be understood that a plurality of lines similar to A and B terminate at the central ofiice, but for the sake of simplicity only the two lines are shown. It is believed that the invention will be fully understood from a description of the operation of the system shown in the drawings, and it will be so described.

Assuming that subscriber A desires to be connected with subscriber B, A will signal the central office in the usual manner, whereupon the operator will insert the answering plug with the cord circuit G into the jack associated with the line A. Cut-off relay 5, associated with these lines, and the answering supervisory relay 6 are thereupon operated. Answering supervisory relay 6 in operating causes the operation of listening relay 7 over a circuit from battery through the normal contact of calling sleeve relay 8, windings 9 and 10 of the listening relay 7, alternate contact of relay 6, resistance 11, sleeve contact of the answering plug and jack and the winding of the cut-off relay Specification of Letters Patent.

Patented Apr. 10, 191?.

Serial No. 119,487.

to ground. The windings 9 and of relay 7 are connected in multiple with answering supervisory lamp 20 forming a low resistance shunt therefor and preventing the lighting of the lamp. Relay 7 when operating, connects an operators telephone set across the talking strands of the cord circuit, whereupon the operator converses with subscriber A.

Upon being advised that subscriber A desires to be connected with the line of subscriber B, the operator inserts the calling plug of the cord circuit G into the jack of line B, whereupon calling sleeve relay 8 and cut-off relay operate, and calling supervisory lamp 17 is lighted. The operation of the calling sleeve relay 8 opens its normal and closes its alternate contacts. The righthand alternate contact is made before the normal contact is broken, and winding 16 of relay 7 is substituted for winding 9. VVindings 9, 10 and 16 are preferably of the same number of turns and resistance. Windings 9 and 10 of listening relay 7 are connected in series-aiding, while windings 10 and 16 are connected in series-opposing, so that when winding 16 is substituted for winding 9, the relay will release its armatures, thereby disconnecting the operators telephone set from the talking strands of the cord circuit. The operator may now signal subscriber B by actuating the usual ringing key 18. Subscriber B, in responding, causes the operation of calling supervisory relay 28, closing a shunt circuit containing a resistance 19 about the calling supervisory lamp 17, which is thereupon elface The subscribers upon finishing the conversation restore their receivers to the switch hooks, whereupon supervisory relays 6 and 28 release, causing the answering calling supervisory lamps and 17 to light to furnish disconnect signals. The operator may then withdraw the plugs from the jacks, whereupon all apparatus returns to normal.

Suppose, however, thatbefo're the plugs were withdrawn from the jacks, that subscriber A should have desired to make a recall; the removal of the receiver from the switchhook by subscriber A causes the intermittent operation of the answering supervisory lamp 20 to furnish a recall signal to the operator. The manner in which this lamp is lighted intermittently or periodically is as follows :-Up0n the restoration of the receiver to the switchhook by subscriber A, answering supervisory relay 6 releases as before described, where-upon relay 25 operates over a circuit from battery through the right-hand alternate contact of relay 8,

right-hand normal contact of relay 25, windings 16 and 10 of relay 7, normal contact of answering supervisory relay 6, left-hand normal contact of relay 25, winding thereof, normal contact of key 26 and the left-hand alternate contact of relay 8 to ground. Relay 25, in operating, completes a locking circuit for itself from battery through the lefthand alternate contact and winding of relay 25, normal contact of key 26 and the lefthand alternate contact of relay 8 to ground. The operation of relay 25 connects, at its right-hand alternate contact, an interrupter 27 in circuit with the windings 16 and 10 of listening relay 7 so that when the answering supervisory relay 6 is again energized in response to the removal of the receiver from the switchhook by subscriber A, the two windings 16 and 10 of listening relay are intermittently or periodically connected in parallel with the lamp 20, whereupon this lamp is caused to be lighted intermittently or periodically to furnish a recall signal to the operator. The operator observing the intermittent operation of the answering supervisory lamp 20, may actuate key 26, thereupon releasing relay 25 and removing the interrupter 27 from circuit, whereupon the windings 16 and 10 of relay 7 will be connected in direct multiple relation to the lamp 20 which is thereby eifaced. The operation of key 26 also connects the operators telephone set across the talking strands of the cord circuit, whereupon the operator may converse with subscriber A and complete any connection desired by this subscriber.

What is claimed is:

1. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a listening relay controlling the connection of the operators telephone to the link circuit, a supervisory relay, a third relay, an energizing circuit therefor including a Winding of the listening relay established upon the deenergization of a supervisory relay, a locking circuit for the third relay established upon the energization thereof for rendering this relay independent of the supervisory relay, a signaling device, and interrupter mechanism brought into circuit with the signaling device by the energization of the third relay and the subsequent energization of the supervisory relay.

2. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a listening relay controlling the connection of the operators telephone set to the link circuit, a supervisory relay, a third relay, an energizing circuit therefor including a winding of the listening relay established upon the deenergization of the supervisory relay, a signaling device, and interrupter mechanism brought into circuit with the signaling device by the energization of the supervisory relay following the energization of the third relay.

3. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a listening relay controlling the connection of the operators telephone set to the link circuit, a supervisory relay, a third relay, an energizing circuit therefor established by the deenergization of the supervisory relay, a signaling device, interrupter mechanism, and a circuit including the signaling device, a winding of the listening relay and interrupter mechanism established by the subsequent energization of the supervisory relay when the third relay is energized.

4. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a listening relay controlling the connecsubsequent energization of the supervisory relay when the third relay is energized.

5. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a listening relay controlling the connection of the operators telephone set to the link circuit, a supervisory relay, a third relay, an energizing circuit therefor including a winding of the listening relay established by the deenergization of the supervisory relay, a locking circuit for the third relay established upon the energization thereof, a signaling device, interrupter mechanism, and a circuit including the signaling device, a winding of the listening relay and the interrupter mechanism established by the subsequent energization of the supervisory relay.

In witness whereof, I hereunto subscribe any name this 8th day of September A. D.,

ARTHUR RAYNSFORD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

